In performing, for example, a fine processing on a substrate (e.g., a semiconductor substrate), a processing liquid is generally ejected on the surface of the substrate. The processing liquid may originally include foreign matters such as particles (fine particles). When the processing liquid flows in a pipe toward an ejecting port, foreign matters such as particles from the pipe may be mixed into the processing liquid. Accordingly, for example, Japanese Patent Laid-Open Publication H7-326570 discloses a substrate processing apparatus in which a filter is disposed in the middle of the route of the processing liquid to remove the foreign matters.